In a dual fiber Mux, the two fiber strands are used to transmit data, the first in one direction, and the second in the opposite direction. One to send and the other to receive. This means that it is possible to use the same wavelength for both transmitting and receiving, as shown below, for example 1470nm in both directions.
The single fiber option is more complex and restricts the number of channels that can be carried, but the cost of fiber is kept down by halving the amount of fiber. Dual Fiber enables more channels to be carried using the same multiplexer, so the multiplexer is no more expensive, but using twice the amount fiber can drastically increase costs.
In conclusion, Multiplexers can be used to save on fiber, enabling multiple channels, such as voice, data, storage and video to be carried over a single fiber simultaneously to optimize and maximize the use of fiber.
